Image acquisition with a conventional optical imaging system, such as, for example, a microscope used for pathology examination of a biological tissue, has a limited depth of field. In order to acquire imaging data representing a three-dimensional piece of tissue, a conventional image acquisition system has to be configured to allow for sequential imaging of different depths of the tissue sample by either refocusing (along the optical axis, such as z-axis) the optical imaging system at different depths of the sample or, in the case when the focal length of the optical system is fixed, repositioning the optical system with respect to the tissue sample to assure that layers of the sample that are located at different depths are being imaged. In the latter case, the optical imaging system may require a sophisticated automated microscope including an automated repositioning unit such as, for example, an electromechanical adjustor of the optics along the local optical axis.
The situation is complicated even further when spectrally-resolved imaging is at issue, such as fluorescent spectral imaging, because it becomes necessary to take multiple sequential exposures of a given layer of the tissue sample at different wavelengths to build a set of hyperspectral images. The latter inevitably increases costs of image acquisition at least in terms of increased acquisition time, reduced fluorescence due to over-exposure (to illumination) of reporter molecules in the tissue sample, and the need to increase the exposure to compensate for such reduction, and increased computer processing time and the need for large computer-storage capacity. The need exists, therefore, for a method and system of hyperspectral image acquisition, where the quality is not compromised by the abovementioned problems.